植物Aux/IAA基因家族生物学功能研究进展

生长素是最重要的植物激素之一,对植物生长发育起着关键调控作用。生长素作用于植物后,早期生长素响应基因家族Aux/IAA、GH3和SAUR等被迅速诱导,基因表达上调。其中Aux/IAA基因家族编码的蛋白一般由4个保守结构域组成,结构域Ⅰ具有抑制生长素信号下游基因表达的作用,结构域Ⅱ在生长素信号转导中主要被TIR1调控进而影响Aux/IAA的稳定性,结构域Ⅲ/Ⅳ通过与生长素响应因子ARF相互作用调控生长素信号。Aux/IAA基因家族在双子叶植物拟南芥(Arabidopsis thaliana)的器官发育、根形成、茎伸长和叶扩张等方面发挥重要作用;在单子叶植物水稻(Oryza sativa)和小麦(Triticum aestivum)中,主要影响根系发育和株型,但大多数Aux/IAA基因的功能尚不清楚。该文主要从Aux/IAA蛋白的结构、功能和生长素信号转导途径方面综述Aux/IAA家族在拟南芥、禾谷类作物及其它植物中的研究进展,以期为全面揭示Aux/IAA家族基因的生物学功能提供线索。

Advances in Biological Functions of Aux/IAA Gene Family in Plants

Auxin is one of the most important plant hormones and plays a key role in regulating plant growth and development. In plants, early auxin responsive gene families, such as Aux/IAA (Auxin/Indole acetic acid repressors), GH3 (Gretchen Hagen3) and SAUR (Small Auxin up RNA), are rapidly induced and up-regulated by auxin treatment. Aux/IAA gene family is generally composed of four conserved domains. Domain I inhibits the expression of downstream genes in the auxin signaling pathway, and domain II is mainly regulated by Transport Inhibitor Response 1 (TIR1) in auxin signal transduction, thus affecting the stability of Aux/IAA. Domain III/IV regulates auxin signaling by interacting with Auxin Response Factor (ARF). Aux/IAA gene family has been reported to play an important role in organ development, root formation, stem elongation and leaf expansion in dicotyledonous Arabidopsis thaliana while in monocotyledonous rice (Oryza sativa) and wheat (Triticum aestivum), Aux/IAA mainly affects root development and plant architecture. However, the functions of most Aux/IAA genes remain unclear and need to further study. In this article, we reviewed the structure and function of Aux/IAA protein, and the auxin signal transduction pathway in Arabidopsis, cereal crops and other plants to provide clues for fully revealing the biofunction of the Aux/IAA gene family.